1. Field of the Invention
This invention relates to an electrophotographic photosensitive member and an electrophotographic device, particularly to an electrophotographic photosensitive member utilizing the work function difference between an electroconductive support and a charge generating material, and an electrophotographic device using the photosensitive member.
2. Related Background Art
Generally speaking, electrophotographic photosensitive members of the Carlson type can be classified broadly into the so called lamination type comprising a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material laminated on one another, and the so called single layer type containing a charge generating material and a charge transporting material in a single layer under mixed state. In the prior art, in both of these photosensitive members, for generation of photoconductive carriers, photoconductive carriers excited by the work function difference between the charge generating material and the charge transporting material and irradiation of light have been separated and injected through the interaction between the work function difference and the electrical field applied. Choice of the charge generating material and the charge transporting material is very difficult, and it has not been necessarily possible to obtain a photosensitive member having good electrophotographic characteristics.
Also, for preparing an electrophotographic photosensitive member having good sensitivity over a wide wavelength region, it has been proposed to provide a charge generating layer in which two or more kinds of charge generating materials are mixed or laminate several kinds of charge generating layers, as described in Japanese Patent Application Laid-Open No. 59-32788. However, in the case of such photosensitive members, because plural kinds of charge generating materials are employed, it becomes further difficult to control the carrier movement between the respective charge generating materials than in the case of using a single kind of charge generating material, and they had the drawback of being unstable with respect to potential stability.